Cushioning and shock absorbing midsole

ABSTRACT

A midsole adapted for attachment to a shoe having multiple layers of varying materials each having a different hardness level. More particularly, the present midsole includes a top, middle and bottom layer wherein all three layers of material have a different hardness range and wherein at least one of the layers is made from thermoplastic rubber (TPR). In one embodiment, the thermoplastic rubber (TPR) layer lies between the top and bottom layers and in another embodiment, the thermoplastic rubber (TPR) layer is the bottom layer. The thermoplastic rubber (TPR) layer may also have a length shorter than the other two layers forming the midsole.

BACKGROUND OF THE INVENTION

The present invention relates generally to the construction of a shoe and, more particularly, to a midsole construction with improved comfort and shock absorption to enhance the comfort of a user's foot.

The footwear industry has seen numerous design features introduced over the years in order to enhance the comfort, cushioning, resiliency and shock absorption capabilities of a shoe. Many of the technological advances have occurred in the sole, particularly the midsole. In most footwear, the midsole often provides both protective cushioning and shock absorption for the user's foot. In an effort to provide improved performance, it is often desirable to vary the support characteristics of the sole from one region to another. A wide variety of soles have been developed to provide variable support for the foot. These advances include using air cushioning systems such as air cavities or air bladders disposed within the sole of a shoe Although a marked improvement over conventional uniform sole constructions has occurred over the years, there still remains a need for a midsole construction that can be adapted to provide additional comfort and shock absorption to the wearer's foot.

It would therefore be desirable to provide an improved midsole construction which is capable of providing increased comfort and shock absorption for the foot without using air cavities and/or air bladders to achieve the same.

SUMMARY OF THE INVENTION

A shoe is generally composed of an upper connected to a sole. The sole of a shoe is generally comprised of an outsole, a midsole, an insole, and on occasion, a sock liner. The present invention is directed to an improved midsole construction having multiple layers of varying materials, each layer of material having a different hardness/softness level.

In one aspect of the present invention, a midsole is provided which includes a three-layered construction, namely, a top layer, a middle layer and a bottom layer. The top layer provides a layer of material between the insole of the shoe and the second or middle layer of the midsole; the middle layer provides cushioning to the foot; and the bottom layer provides additional cushioning and a contacting surface for the outsole. In one embodiment, the top layer is made of a polyurethane material with a hardness in the range of 60-90° Asker C hardness, the middle layer is made of a thermoplastic rubber material with a hardness in the range of 20-65° Asker C hardness, and the bottom layer is made of a polyurethane material with a hardness in the range of 20-50° Asker C hardness. In one embodiment, the middle layer spans the heel portion of the shoe only and includes an upper surface which mates with and attaches to a portion of the bottom surface of the top layer and a bottom surface which mates with and attaches to a portion of the upper surface of the bottom layer. As a result, in the forefront area of the shoe, the bottom surface of the top layer mates with and attaches directly to the upper surface of the bottom layer. The bottom layer provides a layer of material between the outsole of the shoe and the second or middle layer of the midsole in the heel portion of the shoe and a layer of material between the outsole of the shoe and the top layer of the midsole in the forefront portion of the shoe. The three layers of the midsole have varying hardness/softness levels with the top layer being harder than the middle and bottom layers and with the middle layer being harder than the bottom layer. These layers can be attached to each other by any suitable means such as cement adhesion and/or stitching.

In another embodiment, the three layers of material forming the midsole are re-arranged such that the top layer is harder than the middle and bottom layers but the middle layer is softer than the bottom layer. In one embodiment, the bottom layer has an upper surface which mates with and attaches to only a portion of the bottom of the middle midsole layer and the bottom surface thereof mates with and attaches to a portion of the upper surface of the outsole in the heel portion of the shoe. In this particular embodiment, the middle layer of the midsole attaches directly to the upper surface of the outsole in the forefront portion of the shoe.

It is an object of the present invention to provide a midsole which provides enhanced comfort and shock absorption by utilizing multiple layers of varying materials which are likewise of varying hardness/softness levels.

Specific advantages and features of the present midsole construction will be apparent from the accompanying drawings and the description of the several embodiments of the present invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of a shoe constructed in accordance with the teachings of the present invention.

FIG. 2 is an exploded view of the shoe of FIG. 1 showing construction of the midsole.

FIG. 3 is an exploded view of the embodiment of the midsole shown in FIG. 2.

FIG. 4 is an exploded view of another embodiment of the midsole of the shoe shown in FIG. 1.

FIG. 5 is an exploded view of the embodiment of the midsole shown in FIG. 4.

FIG. 6 is a rear elevational view of the bottom layer of the midsole embodiment shown in FIGS. 4 and 5.

It should be understood that the drawings are not necessarily to scale and that the embodiments disclosed herein are sometimes illustrated by fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted. It should also be understood that the invention is not necessarily limited to the particular embodiments illustrated herein. Like numbers utilized throughout the various figures designate like or similar parts or structure.

DETAILED DESCRIPTION

A shoe generally includes an upper and a sole assembly that is affixed to the upper. The sole assembly generally includes an insole, a midsole, and an outsole, each having a peripheral shape designed to conform to the shape of a wearer's foot. To facilitate disclosure of the present invention, reference will be made to various general areas of the foot, such as the heel, arch and forefoot areas. When used to refer to locations on the various sole components, these terms should be interpreted to include those areas of the midsole and outsole that are disposed generally (and not necessarily directly) beneath the corresponding elements of the foot. It should be understood, however, that the boundaries between the heel, arch and forefoot areas are not precise and that these terms should be interpreted loosely and with a great deal of flexibility.

Referring now to the drawings and, in particular, FIGS. 1-3, a first embodiment of a new and improved shoe midsole construction having multiple layers embodying the principles and concepts of the present invention and generally designated by the reference numeral 20 in FIGS. 2 and 3 will be described.

A shoe 12 (FIG. 1) generally includes an upper 14 and a sole assembly 16 that is affixed to the upper 14. Sole assembly 16 typically includes an insole 18, a midsole 20, and an outsole 22 and is attached to the upper 14 using a conventional method of attachment such as an adhesive, stitching or injection molding. In the embodiment illustrated in FIG. 1, the insole 18 is formed as part of the upper 14. The midsole 20 includes three layers, a top layer 24, a middle layer 26 and a bottom layer 28. The midsole 20, as shown in FIGS. 2 and 3, has an upper surface 30 and a bottom surface 32. The top layer 24 of the midsole 20 can be attached via conventional means to either an insole such as insole 18, or to the upper 14, while the bottom surface 32 of bottom layer 28 is attached to the outsole 22 using a conventional method of attachment.

Top layer 24 of the midsole 20 is positioned below the insole 18 and above the middle layer 26 of the midsole 20. The specific material of the top layer 24 may be chosen depending upon the nature and type of shoe in which it will be used. Top layer 24 may be made from a variety of materials including, but not limited to, molded Polyurethane (PU), Polyvinyl Chloride (PVC), Thermoplastic Urethane (TPU), Thermoplastic Rubber (TPR), vulcanized rubber, ethyl vinyl acetate (EVA), rubberlon, or any other synthetic or natural material. The material forming the top layer 24 has a hardness factor greater than the middle and bottom layers 26 and 28 and is generally in the range of 60-90° Asker C hardness. The material and hardness/softness ranges selected will be determined by the type of footwear onto which midsole 20 is intended to be placed.

Lying underneath top layer 24 of the midsole 20 is a middle layer 26 having an upper surface 36 and a bottom surface 40. In the embodiment illustrated in FIGS. 2 and 3, the middle layer 26 only extends across the heel portion of top layer 24 and bottom layer 28 and may be made from a variety of materials including, but not limited to, TPR. The upper surface 36 of middle layer 26 is attached to the bottom surface 34 of the top layer 24 at the heel portion of the sole 16 using a conventional method of attachment, such as adhesive, while the bottom surface 40 of the middle layer 26 is attached to the upper surface 38 of the bottom layer 28 in the heel portion of the sole 16. In contrast, the bottom surface 34 of the top layer 24 is attached directly to the upper surface 38 of bottom layer 28 in the arch and forefoot areas of the sole 16. The middle layer 26 may further be secured to the top layer 24 by utilizing male connection portions, projections or components 42 associated with the bottom surface 34 of the top layer 24 which portions 42 mate with and engage corresponding female connection portions, openings or components 44 associated with the middle layer 26 as best shown in FIG. 3. Regardless of the type of material used for the middle layer 26, the middle layer 26 is softer than the top layer 24 and is generally of a hardness in the range of 20-65° Asker C hardness, and preferably in the range of 40-60° Asker C hardness.

The bottom layer 28 of the present midsole 20 is positioned below the middle layer 26 in the heel area of the sole 16 and below the top layer 24 in the arch and forefront areas of the sole 16 and above the outsole 22. The specific material of the bottom layer 28 may again be chosen depending upon the nature and type of shoe in which it will be used. The bottom layer 28 may be made from a variety of materials including, but not limited to, molded Polyurethane (PU), Polyvinyl Chloride (PVC), Thermoplastic Urethane (TPU), Thermoplastic Rubber (TPR), vulcanized rubber, EVA, rubberlon, or any other synthetic or natural material. The material forming the bottom layer 28 has a hardness factor which is softer than both the top layer 24 and the middle layer 26 and is generally in the range of a 20-50° Asker C hardness, and preferably in the range of 20-40° Asker C hardness. The material and hardness/softness ranges selected will again be determined by the type of footwear onto which midsole 20 is intended to be placed. The upper surface 38 of the bottom layer 28 of the midsole 20 is attached to the bottom surface 40 of the middle layer 26 of the midsole 20 in the heel portion of the sole 16 using a conventional method of attachment, while the upper surface 38 of the bottom layer 28 of the midsole 20 in the arch and forefront areas of the shoe 16 is attached directly to the bottom surface 34 of the top layer 24 of the midsole likewise using conventional means.

In the particular embodiment illustrated in FIGS. 2 and 3, the middle layer 26 of midsole 20 is utilized to provide additional comfort to the wearer of the shoe 12 in that the middle layer 26 acts as a cushioning means to further cushion the heel of the wearer as the heel portion of the shoe 12 strikes the ground during a normal gait. In some embodiments, the middle layer 26 may be comprised of a gel type material which provides increased shock absorption and energy return whereas the top and bottom layers 24 and 28 of the midsole 20 can be made of a dual density lightweight material which likewise provide support and shock absorption. It is also recognized and anticipated that in some embodiments, the middle layer 26 of the midsole 20 may extend beyond the heel portion of the sole 16 to include the arch area and/or forefoot area of the sole 16 as well, or portions thereof. Regardless of the types of materials used for each of the three separate layers 24, 26 and 28 associated with the present midsole construction 20, improved comfort and cushioning is achieved in this particular midsole construction due to the fact that the top layer 24 of the midsole 20 is harder than the middle layer 26 of the midsole 20, which, in turn, is harder than the bottom layer 28 of the midsole 20. Stated another way, the bottom layer 28 is softer than the middle layer 26 which, in turn, is softer than the top layer 24 of the midsole construction 20. This arrangement of layers and hardness factors provides for improved comfort and cushioning to the wearer of the shoe 12.

In another embodiment, referring now to the drawings and, in particular, FIGS. 4-6, a second embodiment of a new and improved shoe midsole construction having multiple layers embodying the principles and concepts of the present invention and generally designated by the reference numeral 46 in FIGS. 4 and 5 will be described.

In the embodiment illustrated in FIG. 4, the insole 18 is again formed as part of the upper 14. The midsole 46 includes three layers, a top layer 48, a middle layer 50 and a bottom layer 52. The midsole 46, as shown in FIGS. 4-6, has an upper surface 54 and a bottom surface 56. The top layer 48 of the midsole 46 can be attached via conventional means to either an insole such as insole 18, or to the upper 14, while the bottom surface 56 of bottom layer 52 is attached to the outsole 22 using a conventional method of attachment.

Top layer 48 of the midsole 46 is positioned below the insole 18 and above the middle layer 50 of the midsole 46. The specific material of the top layer 48 may be chosen depending upon the nature and type of shoe in which it will be used. Top layer 48 may be made from a variety of materials including, but not limited to, molded Polyurethane (PU), Polyvinyl Chloride (PVC), Thermoplastic Urethane (TPU), Thermoplastic Rubber (TPR), vulcanized rubber, EVA, rubberlon, or any other synthetic or natural material. The material forming the top layer 48 has a hardness factor greater than the middle and bottom layers 50 and 52 and is generally in the range of 60-90° Asker C hardness. The material and hardness/softness ranges selected will be determined by the type of footwear onto which midsole 46 is intended to be placed.

Lying underneath top layer 48 of the midsole 46 is a middle layer 50 having an upper surface 58 and a bottom surface 60. Middle layer 50 of the midsole 46 is positioned below the top layer 48 and above the bottom layer 52 of the midsole 46. The specific material of the middle layer 50 may be chosen depending upon the nature and type of shoe in which it will be used. Middle layer 50 may be made from a variety of materials including, but not limited to, molded Polyurethane (PU), Polyvinyl Chloride (PVC), Thermoplastic Urethane (TPU), Thermoplastic Rubber (TPR), vulcanized rubber, EVA, rubberlon, or any other synthetic or natural material. The material forming the middle layer 50 has a hardness factor lesser than the top and bottom layers 48 and 52 and is generally in the range of 20-50° Asker C hardness, and preferably in the range of 20-40° Asker C hardness. The material and hardness/softness ranges selected will be determined by the type of footwear onto which midsole 46 is intended to be placed.

In the embodiment illustrated in FIGS. 4 and 5, the middle layer 50 extends across the entire length of the top layer 48. The upper surface 58 of middle layer 50 is attached to the bottom surface 62 of the top layer 48 using a conventional method of attachment, such as adhesive, while the bottom surface 60 of the middle layer 50 is attached to the upper surface 64 of the bottom layer 52 in the heel portion of the sole 16 and to the upper surface 66 of the outsole 22 in its remaining portion, namely, in the arch and forefoot areas.

The bottom layer 52 of the present midsole 46 is positioned below the middle layer 50 and above the outsole 22 and may be made from a variety of materials including, but not limited to, TPR. The upper surface 64 of bottom layer 52 is attached to the bottom surface 60 of the middle layer 50 at the heel portion of the sole 16 using a conventional method of attachment, such as adhesive, while the bottom surface 56 of the bottom layer 52 is attached to the upper surface 66 of the outsole 22 in the heel portion of the sole 16. In contrast, the bottom surface 60 of the middle layer 50 is attached directly to the upper surface 66 of the outsole 22 in the arch and forefoot areas of the sole 16. The bottom layer 52 may further be secured to the middle layer 50 by utilizing male connection portions, projections, flanges or components 68 associated with the top surface 64 of the bottom layer 52 as best shown in FIG. 6, which portions 68 mate with and engage corresponding female connection portions, cut-outs, cavities, notches or components 70 associated with the middle layer 50 as best shown in FIGS. 4 and 5. The flanges 68 mate with and engage the cut-outs 70 when the bottom layer 52 is attached to the middle layer 58. Regardless of the type of material used for the bottom layer 52, the bottom layer 52 is softer than the top layer 48 and is generally of a hardness in the range of 20-65° Asker C hardness, and preferably in the range of 40-60° Asker C hardness.

In the particular embodiment illustrated in FIGS. 4, 5 and 6, the bottom layer 52 of midsole 46 is utilized to provide additional shock absorption to the wearer of the shoe 12 in that the bottom layer 52 acts as a shock absorption means to further absorb shock to the heel of the wearer as the heel portion of the shoe 12 strikes the ground during a normal gait. It is also recognized and anticipated that in some embodiments, the bottom layer 52 of the midsole 46 may extend beyond the heel portion of the sole 16 to include the arch area and/or forefoot area of the sole 16 as well, or portions thereof. Regardless of the types of materials used for each of the three separate layers 48, 50 and 52 associated with the present midsole construction 46, improved shock absorption is achieved in this particular midsole construction due to the fact that the top layer 48 of the midsole 46 is harder than the middle layer 50 and bottom layer 52 of the midsole 46 and the bottom layer 52 is harder than the middle layer 50 of the midsole 56. Stated another way, the bottom layer 52 is softer than the top layer 48, but is harder than the middle layer 50 of the midsole construction 46. This arrangement of layers and hardness factors provides for improved shock absorption to the wearer of the shoe 12.

Thus, there have been shown and described two embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow. 

1. A midsole of a shoe comprising: a top layer; a middle layer extending at least partially across the length of said top layer and attachable to said top layer; and a bottom layer attachable to said middle layer along at least a portion of its length; said top layer having a hardness greater than said middle and bottom layers, and said middle layer having a hardness greater than said bottom layer.
 2. The midsole of claim 1 wherein said middle layer extends across the heel portion of said top and bottom layers.
 3. The midsole of claim 2 wherein the heel portion of said bottom layer is attached to said middle layer and the remaining portion of said bottom layer is attached to said top layer.
 4. The midsole of claim 1 wherein said top layer includes male connecting portions and said middle layer includes corresponding female connecting portions, said male connecting portions engaging said female connecting portions when said middle layer is attached to said top layer.
 5. The midsole of claim 1 wherein said top layer is made of a polyurethane material.
 6. The midsole of claim 1 wherein said middle layer is made of a thermoplastic rubber material.
 7. The midsole of claim 1 wherein said bottom layer is made of a polyurethane material.
 8. The midsole of claim 1 wherein said top layer has a hardness in the range of 60-90° Asker C hardness.
 9. The midsole of claim 1 wherein said middle layer has a hardness in the range of 20-65° Asker C hardness.
 10. The midsole of claim 1 wherein said bottom layer has a hardness in the range of 20-50° Asker C hardness.
 11. The midsole of claim 1 further including an outsole attachable to the bottom layer of said midsole.
 12. A midsole of a shoe comprising: a top layer made of a material having a hardness in the range of 60-90° Asker C hardness; a middle layer extending at least partially across the length of said top layer and attachable to said top layer, said middle layer being made of a material having a hardness in the range of 40-60° Asker C hardness; and a bottom layer attachable to said middle layer along at least a portion of its length, said bottom layer being made of a material having a hardness in the range of 20-40° Asker C hardness.
 13. The midsole of claim 12 wherein said top layer is made of a polyurethane material.
 14. The midsole of claim 12 wherein said middle layer is made of a thermoplastic rubber material.
 15. The midsole of claim 12 wherein said bottom layer is made of a polyurethane material.
 16. The midsole of claim 12 wherein said middle layer extends substantially across the length of said top layer.
 17. A midsole of a shoe comprising: a top layer; a middle layer attachable to said top layer; and a bottom layer extending at least partially across the length of said middle layer and attachable to said middle layer; said top layer having a hardness greater than said middle and bottom layers, and said bottom layer have a hardness greater than said middle layer.
 18. The midsole of claim 17 wherein said bottom layer extends across the heel portion of said middle layer.
 19. The midsole of claim 18 wherein said bottom layer is attached to the heel portion of said middle layer.
 20. The midsole of claim 17 wherein said middle layer includes female connecting portions and said bottom layer includes corresponding male connecting portions, said male connecting portions engaging said female connecting portions when said bottom layer is attached to said middle layer.
 21. The midsole of claim 17 wherein said top layer is made of a polyurethane material.
 22. The midsole of claim 17 wherein said middle layer is made of a polyurethane material.
 23. The midsole of claim 17 wherein said bottom layer is made of a thermoplastic rubber material.
 24. The midsole of claim 17 wherein said top layer has a hardness in the range of 60-90° Asker C hardness.
 25. The midsole of claim 17 wherein said middle layer has a hardness in the range of 20-50° Asker C hardness.
 26. The midsole of claim 17 wherein said bottom layer has a hardness in the range of 20-65° Asker C hardness.
 27. The midsole of claim 17 further including an outsole attachable to the bottom layer and to a portion of the middle layer of said midsole.
 28. A midsole of a shoe comprising: a top layer made of a material having a hardness in the range of 60-90° Asker C hardness; a middle layer attachable to said top layer and being made of a material having a hardness in the range of 20-40° Asker C hardness; and a bottom layer attachable to said middle layer along at least a portion of its length, said bottom layer being made of a material having a hardness in the range of 40-60° Asker C hardness.
 29. The midsole of claim 28 wherein said top layer is made of a polyurethane material.
 30. The midsole of claim 28 wherein said middle layer is made of a polyurethane material.
 31. The midsole of claim 28 wherein said bottom layer is made of a thermoplastic rubber material.
 32. The midsole of claim 28 wherein said bottom layer extends substantially across the heel area of said middle layer.
 33. The midsole of claim 28 wherein said middle layer includes connecting portions which are cooperatively engageable with corresponding connecting portions associated with said bottom layer when said bottom layer is attached to said middle layer.
 34. The midsole of claim 33 wherein said bottom layer includes a pair of flanges which are cooperatively receivable within a corresponding pair of cut-offs associated with said middle layer. 